Submission #90157

#	Time	Username	Problem	Language	Result	Execution time	Memory
90157		mirbek01	Biochips (IZhO12_biochips)	C++17	0 / 100	2061 ms	12508 KiB

biochips

# include <bits/stdc++.h>

using namespace std;

const int N = 2e5 + 2;

int n, m, rt, a[N], tin[N], tout[N], timer, cur, pre;
long long dp[2][N], x[N];
vector <int> g[N];

void dfs1(int v){
      tin[v] = ++  timer;
      for(int to : g[v]){
            dfs1(to);
      }
      tout[v] = timer;
}

void dfs(int v){
      for(int to : g[v]){
            dfs(to);
      }
      dp[cur][tout[v]] = max(dp[cur][tout[v]], dp[pre][tin[v] - 1] + x[v]);
}

int main(){
      cin >> n >> m;

      for(int i = 1; i <= n; i ++){
            int p;
            cin >> p >> x[i];
            if(!p)
                  rt = i;
            else {
                  g[p].push_back(i);
            }
      }

      dfs1(rt);

      for(int i = 1; i <= n; i ++){
            dp[1][tout[i]] = max(x[i], dp[1][tout[i]]);
      }

      for(int i = 2; i <= m; i ++){
            cur = i % 2;
            pre = cur ^ 1;
            for(int j = 1; j <= n; j ++)
                  dp[pre][j] = max(dp[pre][j - 1], dp[pre][j]);
            for(int j = 0; j <= n + 1; j ++)
                  dp[cur][j] = -1e18;
            dfs(rt);
      }

      long long ans = 0;

      for(int i = 1; i <= n; i ++)
            ans = max(ans, dp[m % 2][i]);

      cout << ans << endl;
}

• Subtask 1: 0 / 100